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Universidade Federal do Rio Grande do Norte (2014)

Modelos de dispersão para extremos de precipitação. Estudo de caso : o nordeste do Brasil

Correia Filho, Washington Luiz Félix

Titre : Modelos de dispersão para extremos de precipitação. Estudo de caso : o nordeste do Brasil

Auteur : Correia Filho, Washington Luiz Félix

Université de soutenance : Universidade Federal do Rio Grande do Norte

Grade : Doutorado em Ciências Climáticas 2014

Résumé
In this thesis used four different methods in order to diagnose the precipitation extremes on Northeastern Brazil (NEB) : Generalized Linear Model s via logistic regression and Poisson, extreme value theory analysis via generalized extre me value (GEV) and generalized Pareto (GPD) distributions and Vectorial Generalized Linea r Models via GEV (MVLG GEV). The logistic regression and Poisson models were used to identify the interactions between the precipitation extremes and other variables based on the odds ratios and relative risks. It was found that the outgoing longwave radiation was the indicator variable for the occurrence of extreme precipitation on eastern, northern and semi arid NEB, and the relative humidity was verified on southern NEB. The GEV and GPD distribut ions (based on the 95th percentile) showed that the location and scale parameters were presented the maximum on the eastern and northern coast NEB, the GEV verified a maximum core on western of Pernambuco influenced by weather systems and topography. The GEV and GPD shape parameter, for most regions the data fitted by Weibull negative an d Beta distributions (ξ < 0) , respectively. The levels and return periods of GEV (GPD) on north ern Maranhão (centerrn of Bahia) may occur at least an extreme precipitation event excee ding over of 160.9 mm /day (192.3 mm / day) on next 30 years. The MVLG GEV model found tha t the zonal and meridional wind components, evaporation and Atlantic and Pacific se a surface temperature boost the precipitation extremes. The GEV parameters show the following results : a) location ( ), the highest value was 88.26 ± 6.42 mm on northern Maran hão ; b) scale ( σ ), most regions showed positive values, except on southern of Maranhão ; an d c) shape ( ξ ), most of the selected regions were adjusted by the Weibull negative distr ibution ( ξ < 0 ). The southern Maranhão and southern Bahia have greater accuracy. The level period, it was estimated that the centern of Bahia may occur at least an extreme precipitatio n event equal to or exceeding over 571.2 mm/day on next 30 years.

Mots Clés : Modelos vetoriais lineares generalizados ;Regressão logística ;Regressão de poisson ;Radiação de onda longa ;Variabilidade interanual da precipitação.

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